The present invention relates generally to less-invasive surgery of the cardiovascular system. More specifically, the invention relates to thoracoscopic devices and techniques for performing surgical procedures within the heart and great vessels while the heart is beating.
Tens of thousands of people are born each year with congenital defects of the heart. Some of the more common types of congenital cardiac defects include atrial septal defect (ASD), ventricular septal defect (VSD), and patent ductus arteriosis (PDA). An ASD is a hole in the cardiac septum between the left and right atria, while a VSD is a hole in the septum between the left and right ventricles. Patent ductus arteriosis is incomplete closure of the opening between the pulmonary artery and the aorta that is present during fetal development. These conditions may cause blood to abnormally shunt from the right side of the heart to the left side of the heart without being properly oxygenated in the lungs, so that the body tissues supplied by the blood are deprived of oxygen. In addition, blood in the left side of the heart may shunt back to the right side through the defect rather than being pumped into the arterial system, causing abnormal enlargement of the right chambers of the heart.
ASD""s, VSD""s and PDA can frequently be surgically repaired with significant success. Smaller defects may be reparable by simply suturing the defect closed, while larger defects may require a patch of polyester, expanded polytetrafluoroethylene, or a portion of the patient""s own pericardium to be sutured into the heart to cover and occlude the defect.
Ordinarily, such surgery is performed using open-chest techniques while the heart is under cardioplegic arrest and circulation is maintained by cardiopulmonary bypass. Using such techniques, a gross thoracotomy is created in order to gain access to the heart and great vessels, facilitating clamping and cannulation of the aorta for inducing cardioplegic arrest, and allowing instruments to be introduced into the chest cavity and into the heart to perform the surgical repair. The necessity of stopping the heart significantly heightens the risks attendant such procedures, particularly the risks of causing ischemic damage to the heart muscle, and of causing stroke or other injury due to circulatory emboli produced by aortic clamping and vascular cannulation. In addition, the creation of a gross thoracotomy produces significant morbidity and mortality, lengthens hospital stay and subsequent recovery, increases costs, and worsens the pain and trauma suffered by the patient. Moreover, many congenital defects are repaired in children under the age of ten years for whom the morbidity and mortality of open-chest surgery and cardioplegic arrest can be even greater than for older patients.
In an effort to avoid the necessity of grossly opening the chest and stopping the heart, a number of intravascular devices have been developed for repair of ASD""s, VSD""s, and PDA. For example, U.S. Pat. No. 3,874,388 to King et al. discloses an intravascular delivery catheter introduced intraluminally from a peripheral vein into the right side of the heart which can be used to position an artificial umbrella-like patch across a septal defect and to anchor the patch to the cardiac septum. Other intravascular delivery devices and artificial patches for the repair of septal defects can be seen in U.S. Pat. Nos. 5,334,217, 5,284,488, 4,917,089, 4,007,743, and PCT Application No. PCT/US92/10141.
While intravascular approaches to the repair of congenital defects may provide certain advantages, the most significant of which is the elimination of the need for gross thoracotomy and cardioplegic arrest, these techniques have suffered from a number of problems. One such problem is the difficulty in manipulating the artificial patches into position across a defect using only the proximal end of a long and flexible delivery catheter positioned through a tortuous right lumen. Also problematic is the inadequacy of fixation of endovascularly-placed patches, creating a tendency of such patches to migrate or embolize after placement, which can allow blood to again shunt through the defect. In addition, once such a patch has been placed and the delivery catheter detached from the patch, relocating and repositioning the patch with the catheter is difficult, if not impossible, and may require open surgical correction. Moreover, in young children, the size of the peripheral vessels is extremely small, and damage to such vessels could have serious effects upon the growth of the child. Thus, the size of the devices which can be introduced through such vessels is greatly limited.
In addition to ASD, VSD, and PDA, various other types of cardiac disease also may be diagnosed and treated by intervention within the interior chambers of the heart. For example, some cardiac arrhythmias such as ventricular tachycardias, supraventricular tachycardias, and atrial fibrillation, may be diagnosed by obtaining access into an interior chamber of the heart and by performing electrophysiological mapping to identify abnormal conduction pathways. Once these abnormal conduction pathways are identified, in some cases the disease may be treated by ablating selected cardiac tissue using radiofrequency (RF) energy or a medical laser to eliminate the abnormal pathways. A number of endovascular approaches have been developed which attempt to allow intracardiac mapping and ablation using catheters introduced transluminally from peripheral vessels into the heart. Such devices are disclosed, for example, in U.S. Pat. Nos. 4,960,134, 4,573,473, 4,628,937, and 5,327,889. However, endovascular mapping and ablation devices suffer from many of the same problems suffered by endovascular septal defect repair devices, including a lack of control and precise positionability from the proximal end of these highly flexible and elongated devices, the significant size constraints of peripheral vessels, and the inability to position the devices in all potentially diseased sites within the heart.
What are needed, therefore, are devices and methods to enable the repair of ASD, VSD, PDA, and other congenital defects, as well as cardiac arrhythmias and other diseases of the heart, which eliminate the need for gross thoracotomy and cardioplegic arrest, but which overcome the forementioned problems with intravascular techniques. The devices and methods should facilitate a high level of control for precise manipulation within the heart. The devices and methods should produce a septal defect or PDA repair which is reliable and long-lasting, and should not be susceptible to migration, embolization, or reopening of a defect. The devices and methods for septal defect and PDA repair should allow the position of a repair patch to be inspected after initial placement and to be repositioned if necessary. Finally, the devices and methods should not risk damaging the peripheral vessels of the patient, nor should the size and configuration of the devices be limited by the size of the patient""s peripheral vessels.
The invention provides devices and methods that facilitate thoracoscopic access into the interior of the heart while the heart is beating. This intracardiac access can be used to perform a variety of diagnostic and treatment procedures within the heart without the need for a gross thoracotomy or cardioplegic arrest. The invention provides devices and methods for the performance of a number of different procedures including the repair of ASD, VSD, PDA, and other cardiac abnormalities, electrophysiologic mapping and ablation for the treatment of cardiac arrhythmias, as well as a variety of other intracardiac procedures that can be performed thoracoscopically on a beating heart.
In a first aspect of the invention, a tubular access device is provided for accessing an interior chamber of a beating heart. The access device includes an elongated tubular body configured to extend percutaneously through an intercostal space between the ribs of the chest and through a muscular wall of the heart, and an inner lumen extending through the tubular body which provides an access channel into the heart. In an exemplary embodiment, the tubular access device has a length of at least 10 cm, and the inner lumen has a diameter of at least 5 mm. Preferably, the tubular access device is rigid to facilitate responsive and precise positionability from its proximal end.
In one embodiment, the access device includes means near a distal end thereof for scaling peripherally around a surrounding penetration in the muscular heart wall through which the access device is positioned. The sealing means may comprise one or a pair of inflatable balloons, a radially-expandable portion of the tubular body, or a flange at the distal end of the body. A purse string suture or other tissue-gathering means may be applied to the muscular heart wall surrounding the tubular body and tightened to prevent blood from flowing through the penetration around the access device.
The invention may further include an obturator positionable within an inner lumen of the tubular access device. The obturator may have means at its distal end for penetrating the muscular wall of the heart. The penetrating means may comprise a blade, radiofrequency electrode, or other type of cutting element. In a preferred embodiment, the obturator further includes means for selectively exposing the penetrating means, which may include a movable actuator for extending and retracting the cutting means from the distal end of the obturator.
The access device may include a hemostasis valve in the inner lumen to prevent blood flow out of the heart through the inner lumen, and to allow instruments to be introduced through the inner lumen while maintaining hemostasis in the inner lumen. The hemostasis valve may be disposed at either the proximal end or the distal end of the access device. Alternatively, when the access device is utilized in the lower-pressure right atrium, right ventricle, or left atrium, the access device may be positioned in a generally vertical orientation so that blood flow through the inner lumen is prevented by the pressure head of blood within the inner lumen being greater than the pressure in the cardiac chamber, eliminating the need for a hemostasis valve.
With the access device positioned through an intercostal space and through a wall of the heart, a straight and relatively large channel directly into the interior of the heart is available for the introduction of devices for diagnostic and treatment procedures. In a preferred embodiment, the invention provides systems and methods for repairing atrial and ventricular septal defects through the inner lumen of the access device. The septal defect repair system includes, in addition to the above-described access device, a closure means for closing or occluding the septal defect, and a means for introducing the closure means through the access device into the interior of the heart.
In a first embodiment, the closure means comprises a patch that may be attached to the cardiac septum to cover and occlude the septal defect. The patch includes a collapsible frame, and a flexible patch material attached to the frame. The flexible patch material may be an artificial biocompatible material such as polyester or expanded polytetrafluoroethylene, or a portion of the patient""s pericardium or other natural body membrane. The frame is configured to support the patch material at its outer edges in a generally flat configuration, and is sufficiently rigid to retain its shape against the pressure of blood within the heart, while having sufficient flexibility and resiliency to be collapsible for introduction through the inner lumen of the access device. In an exemplary embodiment the frame comprises a hub and a plurality of spokes extending radially outward from the hub. A circumferential wire or suture thread extending between the outer tips of the spokes may be provided to continuously support the outer edges of the patch. The hub is a rigid material such as stainless steel, is small enough to fit within the inner lumen of the access device, and is configured to be detachably coupled to the distal end of an delivery shaft (described below). The spokes are flexible, resilient wires of Nitinol(trademark) or other material exhibiting similar super-elastic characteristics. The patch may be mounted to the frame by sutures, heat welding, adhesive, or other means.
The patch includes a means for securing the patch to the cardiac septum. The securing means may comprise a second patch coupled to a central portion of the first patch and parallel thereto such that one patch may be positioned through the septal defect on the left side of the cardiac septum and the second patch positioned on the right side of the cardiac septum, with the outer edges of the two patches compressively engaging the cardiac septum between them. For example, in the hub and spoke embodiment describe above, two sets of spokes may be mounted to the hub and a patch mounted to each set of spokes so that the two patches are generally parallel to each other and spaced slightly apart. Alternatively, the securing means may comprise a plurality of flexible wire struts coupled to a central part of the frame such that the outer ends of the struts will compressively engage the cardiac septum on the side opposite that on which the patch is positioned. Like the patch, the securing means is collapsible to allow introduction through the inner lumen of the access device. To facilitate secure fixation to the septum, the frame or the securing means may include pins or spikes pointing generally perpendicular to the patch to partially penetrate the cardiac septum when the patch has been positioned across the defect, preventing migration of the patch.
The patch is introduced into the heart and positioned across the septal defect by means of a rigid delivery shaft which may be positioned through the inner lumen of the access device. The delivery shaft includes an interior lumen or aperture at its distal end for receiving the patch and securing means in a collapsed configuration. The delivery shaft further includes a means for deploying the patch and the securing means, which may comprise a rod slidably disposed in a lumen through the delivery shaft. The rod includes means at its distal end for releasably coupling to the patch, such as a threaded extension which couples to a threaded hub in the patch frame. The rod may be advanced distally relative to the delivery shaft to deploy the patch from the aperture into the heart chamber on the side of the cardiac septum further away from the point of introduction, e.g., the left atrium if the device has been introduced into the heart through the right atrium. The patch is positioned against the septum, and the securing means is deployed on the side of the cardiac septum opposite the patch, e.g., the right atrium in the aforementioned case. The rod may then be decoupled from the patch and the delivery shaft is removed from the patient through the access device.
Advantageously, the delivery shaft and deployment means are configured to allow the patch to be re-collapsed and repositioned if the position of the patch is not satisfactory after initial deployment. In one embodiment, the rod is drawn proximally relative to the delivery shaft, whereby the patch is collapsed by engagement with the distal end of the delivery shaft. The patch securing means may be collapsed in a similar manner, or by a separate mechanism. In an exemplary embodiment, one or more wires or sutures extend through a lumen in the delivery shaft and are coupled to the securing means, e.g. to the outer ends of the spokes or struts of the securing means. By exerting tension on the wires, the securing means is drawn proximally into a collapsed configuration to allow it to be received in the aperture in the delivery shaft. This allows the patch and securing means to be drawn back into the aperture in the delivery shaft and redeployed at the desired position.
In an alternative embodiment, the septal defect closure means comprises a suturing device for applying at least one suture across the septal defect. The suturing device includes a rigid delivery shaft suitable for introduction through the inner lumen of the access device, and a plurality of needle holders mounted to the delivery shaft for releasably holding at least two needles connected by a suture thread. The needle holders are movable between a contracted position suitable for introducing the needles through the septal defect into the cardiac chamber on the opposite side of the septum, and an expanded position in which the tips of the needles are aimed proximally toward the cardiac septum on opposing sides of the septal defect. In one embodiment, the needle holders are mounted on opposing sides of a balloon which may be deflated during introduction through a septal defect and then inflated to move the needles into the expanded position. The needle holders are then pulled proximally so that the needles penetrate the cardiac septum. A means is mounted to the delivery shaft for capturing the distal tips of the needles after penetrating the septum. For example, the needles may have barbed tips which engage a porous fabric disk slidably mounted to the delivery shaft. The needle capture means is retracted to draw the needles through the septum and out of the heart through the inner lumen of the access device. In this way, a plurality of sutures may be applied to the cardiac septum simultaneously. Knots may then be tied in the sutures extracorporeally, and, using a long-handled endoscopic knot-pusher, pushed through the access device into the heart so as to tighten the sutures and draw the opposing sides of the septal defect together.
In a further aspect of the invention, a method of accessing an interior chamber of a beating heart is provided. According to the method of the invention, a penetration is formed in a muscular wall of the heart into an interior chamber of the heart, and a distal end of a tubular access device having an inner lumen is positioned through the penetration. The penetration may be formed with various types of endoscopic cutting devices, but, in a preferred embodiment, is formed with the cutting means at the distal end of the obturator, which is positioned in the inner lumen of the access device. This allows the access device to be introduced immediately upon forming the penetration, minimizing blood loss through the penetration. The method further includes the step of forming a hemostasis seal between the access device and the penetration to inhibit blood loss through the penetration. This step may include placing a purse string suture in the wall of the heart around the penetration, inflating a balloon mounted to the access device within the chamber of the heart, or radially-expanding a portion of the access device within the penetration.
The method also includes preventing blood flow out of the chamber of the heart through the inner lumen of the access device. This may be accomplished by positioning the access device in a vertical orientation so that the pressure head of blood in the inner lumen is sufficient to prevent blood flow out of the heart, or a hemostasis valve may be provided in the inner lumen.
While the method of accessing an interior chamber of the heart may find use in open-chest surgical procedures, it is preferably performed using thoracoscopic techniques, wherein the ribs and sternum remain intact and are not significantly retracted during each step of the procedure. Using such techniques, a working space may be created in the patient""s chest cavity by collapsing one of the patient""s lungs or using jet ventilation techniques. A viewing scope such as an endoscope or endoscopic surgical microscope may then be introduced through an intercostal space into the working space to view the exterior of the heart while the penetration is formed and the access device is introduced. The viewing scope may include a video camera to provide a video image of the heart for display on a monitor which can be viewed during the procedure. Alternatively, the heart may be viewed directly through a lens on the viewing scope or through a trocar sleeve positioned in an intercostal space.
The method of accessing an interior chamber of the heart facilitates the performance of a variety of intracardiac diagnostic and treatment procedures. While it may be desirable to place the patient on cardiopulmonary bypass and arrest the heart during certain procedures, the invention facilitates the performance of a number of cardiac procedures while the heart is beating, without the need for cardiopulmonary bypass or cardioplegic arrest, and with significantly reduced risk of injury resulting from embolism.
In a further aspect of the invention, a method is provided for closing a cardiac septal defect in a patient""s heart. The patient is first placed under general anesthesia. The method is initiated by positioning the distal end of the tubular access device in an interior chamber of the heart and creating a hemostatic seal around the access device, as described above. These steps are preferably performed under visualization by means of an endoscope or other percutaneous visualization device. One or more instruments are then passed through the inner lumen of the access device and out of the distal end thereof. The one or more instruments are then used to close the septal defect.
In a preferred embodiment, the method of the invention is performed while the patient""s ribs and sternum remain intact and unretracted, and while the patient""s heart is beating. Access into the chest cavity is obtained through small percutaneous incisions or punctures in the intercostal spaces between the ribs. Trocar sleeves, ports, or other types of percutaneous access cannulae may be placed in these incisions or punctures to protect and retract surrounding tissue to facilitate introduction of instruments into the chest cavity.
Usually, the interior chamber of the heart will be the right atrium, right ventricle, or left atrium, in which blood pressure is lower than in the left ventricle. Preferably, the access device is positioned in a vertical orientation, usually from a lateral side of the chest, with the distal end of the access device disposed in the interior chamber. In this way, the static pressure head of blood within the inner lumen is equal to the pressure within the interior chamber, preventing the flow of blood out of the interior chamber through the inner lumen. In an exemplary embodiment, small incisions and/or access ports are placed in the third, fourth, fifth, or sixth intercostal spaces on a lateral side of the chest. At least three such ports are usually required, one for introduction of the access device, one for introduction of a visualization device such as an endoscope, and one for introduction of other instruments for suturing, retraction, and other purposes.
Visualization within the interior of the heart may be provided by various means. Preferably, an ultrasonic probe is positioned in the patient""s esophagus, on the surface of the patient""s chest, or in the chest cavity adjacent or in contact with the exterior of the heart to ultrasonically image the interior of the heart. Alternatively, an endoscopic with a translucent bulb or balloon over its distal end may be introduced into the heart through the access device or through a separate incision in the wall of the heart to allow video-based or direct visualization of the interior of the heart. An angioscope introduced into the heart endovascularly through a peripheral vessel may also be used for intracardiac visualization. Fluoroscopy is an additional technique for visualization.
The septal defect may be repaired in any of several ways. A patch may be attached to the cardiac septum to cover the defect, or the defect may be sutured closed. As described above, the patch may be an artificial biocompatible material, or it may be created out of a portion of the patient""s pericardium or other natural membrane in the patient""s body. The patch is introduced through the inner lumen of the access device by means of a rigid delivery shaft to which the patch is detachably coupled, allowing the patch to be positioned with a high degree of control and precision. The patch is inserted through the septal defect into the left side of the heart in a collapsed configuration, then expanded to cover the defect. When the patch has been positioned across the defect, the interior of the heart is visualized by ultrasonic imaging, fluoroscopy with contrast dye injection, or other means to determine whether the defect has been closed adequately. If not, the patch may be retrieved and repositioned with the delivery shaft. Once positioned properly, the patch is anchored to the cardiac septum, preferably by the compressive force of an opposing patch, frame or series of struts disposed on the right side of the septum. A number of pins or spikes may be provided on the patch to partially penetrate the septum to prevent migration. The patch is then released from the delivery shaft.
In those embodiments in which the patch comprises a portion of the pericardium or other natural membrane, the invention allows the portion of membrane to be harvested from the patient""s body and then affixed to a frame outside of the body cavity. Preferably, the membrane is harvested using instruments introduced percutaneously through intercostal spaces, while keeping the ribs and sternum intact. The membrane may be affixed to the frame using sutures, tissue adhesive, staples, or the like. Once the membrane is attached to the frame, the two may be coupled to the delivery shaft and introduced through the inner lumen of the access device into the heart for attachment to the cardiac septum.
Where the septal defect is to be closed by means of sutures, at least two needles connected by a length of suture are introduced through the access device and inserted through the defect while the needles are in a radially retracted position. The needles are held in needle holders coupled to the end of an delivery shaft. After insertion through the defect, the needles are repositioned into a radially expanded position in which they are further separated from one another. A balloon, expandable wire basket, scissors-type linkage, or camming device may be used for this purpose, or the needles may be held in needle holding rods having a shape memory so as to assume the radially expanded configuration when unrestrained. The needles are then drawn through the cardiac septum while in the expanded position. The needles are captured, and both ends of the length of suture are then tensioned to close the defect. Usually the length of suture is long enough to allow the suture needles to be drawn outside of the body cavity through the inner lumen of the access device. Knots are then formed extracorporeally and pushed through the access device up to the cardiac septum using an endoscopic knot pusher. The sutures are trimmed using endoscopic scissors, and the repair is examined using one of the aforementioned visualization techniques.
Once the septal defect has been closed, the access device is withdrawn from the penetration in the wall of the heart. If a balloon or a radially expanding portion of the access device has been utilized for hemostasis, it is first deflated or radially contracted. As the distal end of the access device is withdrawn, the purse string suture in the heart wall surrounding the access device is pulled tight, closing the penetration. Knots are then formed in the purse string suture, either intracorporeally using endoscopic instruments, or extracorporeally, after which the knots are pushed into the body cavity and against the heart wall using an endoscopic knot pusher. Alternatively, the penetration in the heart wall may be closed using endoscopic suturing or stapling techniques after the access device has been withdrawn. All access ports are then withdrawn, percutaneous incisions and punctures are closed, and the patient is recovered from anesthesia.
In a further aspect of the invention, devices and methods are provided for performing electrophysiological procedures within the heart. Such procedures include electrophysiological cardiac mapping and ablative treatment of cardiac arrhythmias, including ventricular and supraventricular tachycardias and atrial fibrillation. The invention provides devices and methods for diagnosis and treatment of such diseases by accessing the interior of the heart through the intracardiac access device described above. Such techniques avoid the need for a gross thoracotomy, and offer more control and precision in diagnosing and treating these diseases than are offered by intravascular clectrophysiological treatment techniques.
An clectrophysiological device according to the invention comprises a rigid shaft suitable for introduction through the inner lumen of the access device. A deflectable tip is attached to the distal end of the shaft. The deflectable tip has at least one and usually a plurality of electrodes mounted to it. A steering means is provided in the shaft for deflecting the tip into the desired orientation. The electrodes are electrically coupled to a connector at the proximal end of the shaft, which may be connected to a sensitive electrocardiogram (ECG) monitoring apparatus [radiofrequency generator?]. The deflectable tip may be introduced into a chamber of the heart through the access device, and the electrodes positioned against a site on an interior wall of the heart to perform an clectrophysiological procedure. For example, a plurality of electrode bands may be mounted in a spaced-apart relationship on the deflectable tip, and the voltage difference can be measured across selected electrodes to identify aberrant conduction pathways in the heart wall, a process known as cardiac mapping. In addition, radiofrequency current may be delivered through one or more electrodes to ablate tissue at selected sites on the heart wall.
In a second embodiment, an electrophysiological device according to the invention comprises an expandable electrode array mounted to the distal end of the rigid shaft. The electrode array includes a plurality of electrodes mounted to an expandable support structure such as a frame, basket, balloon, or series of rods. The support structure is coupled to an actuator at the proximal end of the shaft to facilitate selective deployment of the electrode array from a contracted configuration, in which it may be introduced through inner lumen of the access device, to an expanded configuration, in which the electrodes are spread apart into a two-dimensional or three-dimensional array. In one embodiment, the electrode array is configured to conform generally to the shape of an interior chamber of the heart in the expanded configuration. In this way, the electrodes may be positioned in a pattern along the interior walls of the heart chamber to facilitate mapping or ablation of a large area without moving the device.
The electrophysiological devices of the invention are particularly advantageous in that they offer a high degree of control and precision in positioning within the heart. Because the devices are manipulated by means of a rigid shaft that spans only the relatively short distance from the interior of the heart to the exterior of the chest cavity, the electrodes can be easily and precisely positioned at most locations within the heart chamber. Moreover, because the electrophysiological devices are not introduced endovascularly, they are not limited in size and configuration by blood vessel size. The devices may therefore have electrodes which are larger than those of endovascular electrophysiology devices, permitting the delivery of greater amounts of energy to a tissue site. Further, the electrodes may be greater in number and spread out over a larger area than endovascular electrophysiology devices, allowing a greater area of a heart chamber to be mapped or ablated without moving the device, thus increasing the precision and efficiency of the procedure.
In a method of electrophysiological intervention according to the invention, the tubular access device is introduced into a chamber of the heart in the manner described above. An electrophysiology device including at least one electrode coupled to the distal end of a shaft is introduced through the tubular access device into the heart chamber. The electrode is positioned at a tissue site on a wall of the heart chamber, and either radiofrequency current is delivered to the tissue site through the electrode, or electrical potential is sensed between two or more selected electrodes. This technique may be used for either cardiac mapping or ablation of tissue. The method may further include deflecting a flexible tip attached to the shaft so that the electrode is positioned away from a longitudinal axis of the shaft, permitting the electrode to be positioned at various locations within the heart chamber. Alternatively, the method may include a step of expanding an electrode array into an expanded configuration within the heart chamber. In the expanded configuration, a plurality of electrodes of the electrode array are positioned in a two or three dimensional array which may be positioned adjacent a treatment area on an interior wall of the heart chamber. Electrical potentials in the heart wall tissue may then be sensed between selected electrodes, or radiofrequency current may be delivered to the treatment area through one or more electrodes of the electrode array.
The method may be performed in either the right side or the left side of the heart, and in either the atria or the ventricles. In ventricular procedures, because it may be undesirable to form a penetration in the wall of a ventricle, the electrophysiology device may be introduced through the access device into an atrium, from which it is advanced through the tricuspid valve or mitral valve into the ventricle. Alternatively, the electrophysiology device may be positioned transeptally through a puncture in the cardiac septum, wherein, after electrophysiological treatment is complete, the device is withdrawn and the septal puncture closed.
The devices and methods of the invention may also be useful in combination with other types of cardiac treatment procedures. For example, the electrophysiology devices of the invention may be useful for mapping conduction pathways in the heart, which are then treated by means of thoracoscopic, endovascular, or open-chest techniques. Alternatively, thoracoscopic or endovascular techniques may be used for mapping, and the intracardiac electrophysiological devices of the invention may then be used for ablation or other treatments. In one exemplary procedure, a thoracoscopic mapping device is introduced through an intercostal port in the chest for mapping cardiac conduction pathways on the exterior surface of the heart. The intracardiac electrophysiology device of the invention is then utilized in the interior of the heart to perform ablation, utilizing the mapping information generated on the exterior of the heart. Such a technique could be used for treatment of ventricular and supraventricular tachycardias. Similarly, to treat atrial fibrillation, intracardiac mapping may be performed using the electrophysiology device of the invention, and thoracoscopic or endovascular cutting or ablation instruments may then be utilized through intercostal ports to perform a Cox xe2x80x9cmazexe2x80x9d-type surgical transection of the atrium, whereby the mapping information is used to make precise incisions or ablation lines in the myocardium to create a directed conduction pathway between the sinoatrial node and the atrioventricular node.
By providing access to the interior of the heart without requiring a gross thoracotomy and without the need to induce cardioplegic arrest, the invention enables a variety of intracardiac procedures to be performed on a beating heart. In addition to septal defect repair and the electrophysiological procedures described above, these procedures may include repair of other types of congenital defects, transmyocardial laser revascularization, mitral, aortic, pulmonary, or tricuspid valve inspection and repair, pulmonary thrombectomy, intracardiac inspection, removal of growths, myxomas, neoplasms, hypertrophic obstructive cardiopmyopathy and vegetations, and other diagnostic and treatment procedures.
The nature and advantages of the invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying exemplary drawings.